Digital subscriber line (DSL) technology was initially deployed to provide data-only service as a replacement for slower-speed, dial-up modems. Incumbent local exchange carriers (ILECs), competitive local exchange carriers (CLECs), and other telecommunication providers have begun to explore offering voice-over-Digital-Subscriber-Line (VoDSL) service, and other voice-over-broadband services, to deliver integrated voice and data services.
A central component of a typical voice-over-broadband system is the voice gateway. The voice gateway receives telecommunications information in a packetized format from the customer premises via network ports in a network interface, reformats the packetized data from the network ports into a telephony format, and sends the telephony data to a public switched telephone network (PSTN) via telephony ports in a telephony interface. Likewise, telephony data from the PSTN is received at the telephony ports, packetized, and then transmitted to users via the network ports.
Typically, the telephones, computers, and other telecommunication equipment at the customer premises are connected to the voice gateway via an ATM network, the network interface is a broadband interface, and the network ports are wide area network (WAN) ATM ports. The network ports may connect to an ATM/IP network, a Digital Subscriber Line Access Multiplexor (DSLAM), or a Cable Modem Termination System (CMTS), for example. The network ports may reside on removable cards or blades that plug in to the voice gateway. Several different techniques are available for packetizing telecommunication information and for transporting information such as packetized voice. Those techniques include, without limitation, the Voice-over-Internet-Protocol (VoIP) protocol, the Voice-over-Asynchronous-Transfer-Mode (VoATM) protocol, the ATM Adaptation Layer Type 2 Broadband Loop Emulation Service (AAL2 BLES) protocol, and the Voice over IP over ATM (VoIPoATM) protocol for transporting IP over ATM Adaptation Layer Type 5 (AAL5).
In any case, the primary function of a voice gateway is to serve as a bridge between existing telephony platforms (which use Class-5 switches, GR-303 and TR-08 interfaces, V5.X switching and signaling protocols, Customer Premises Equipment Alerting Signal (CAS) tones, etc.) and modern data network interfaces (which use interfaces and architectures such as Cable Multimedia Terminal Adapters (MTAs), DSL DSLAM, Wireless Local Loop, etc.). When designing, deploying, and operating a voice gateway, it is often necessary to test the voice gateway. For example, it would be beneficial to test the end-to-end operation of a voice gateway to ensure that the different subsystems interoperate properly after the gateway is assembled but before it is deployed in the field.
Some forms of conventional test equipment are well suited for testing conventional telephony systems. Other types of test equipment are well suited for testing data networking equipment. Voice gateways, however, include equipment for communicating with telephony platforms, equipment for communicating with data network platforms such as broadband, and equipment for converting information from each of those platforms for use one the other. Conventional test equipment does not provide the functionality needed to effectively test devices like voice gateways which bridge the telephony and data network platforms.